The present invention relates generally to the field of fuel cell fabrication and more particularly to fuel cell part tracking methods and apparatus.
Solid oxide fuel cells (“SOFC's”) are solid-state devices which use an oxygen ion conducting ceramic electrolyte to produce electrical current by transferring oxygen ions from an oxidizing gas stream at the cathode of the fuel cell to a reducing gas stream at the anode of the fuel cell. The oxidizing flow is typically air, while the fuel flow may be a hydrocarbon fuel, such as methane, natural gas, pentane, ethanol, or methanol. The fuel cell, operating at a typical temperature between 750° C. and 950° C., enables the transport of negatively charged oxygen ions from the cathode flow stream to the anode flow stream, where the ion combines with either free hydrogen or hydrogen in a hydrocarbon molecule to form water vapor and/or with carbon monoxide to form carbon dioxide. The excess electrons from the negatively charged ion are routed back to the cathode side of the fuel cell through an electrical circuit completed between anode and cathode, resulting in an electrical current flow through the circuit.
Fuel cell stacks are frequently built from a multiplicity of cells in the form of planar elements, tubes, or other geometries. Fuel cell stacks, particularly those with planar geometry, often use seals between electrolyte and interconnect surfaces to contain fuel and air at various locations within the stack. The stacks are often internally manifolded for fuel and/or air flow, and the ceramic electrolyte material may include internal openings or holes to accommodate fluid flow within the stack.
The fabrication of fuel cell stacks may involve a large number of complex process steps. As examples, the manufacture of fuel cell stack components may include multiple pressing, sintering, conditioning, and coating steps. Each process step needs to be carefully designed and process interactions considered and monitored in order to create a functioning product with high yield. Each process step and its associated equipment/material may contribute to the functioning of the end product, thus tracking process steps, equipment/material, and fuel cell stack parts themselves may be key to creating a functioning product.